The invention is particularly directed towards the germicidal disinfecting of the skin surfaces on dairy cow teats and additionally providing a germicidal barrier film such that the disinfected teat skin is physically protected from the unhindered reintroduction of pathogens back onto the teat skin surface and such that a plug of this film is formed at the opening of the mammary sphincter providing protection from the introduction of pathogenic organisms into the mammary canal. The control of pathogenic organisms on the teat skin of dairy cows is a major goal of the dairy industry. Contact with the bovine mammary gland by a pathogenic microorganism, usually bacteria but occasionally yeast or fungi, can result in the disease of mastitis. Mastitis is a serious infection which can in severe cases, cause death to the dairy cow and even in much milder cases can result in long term damage to the cow, loss of milk production for the dairy farmer and overall an unacceptable increase in costs to the farmer. Mastitis is indeed widely considered to be the single most costly disease in the dairy industry. Efforts to control the presence of infectious agents date back to the early 1900's but the success of these efforts was limited by the unavailability of effective germicidal agents. The incidence of mastitis has decreased over the last twenty-five years due to the realization that proper hygiene, particularly with regard to the udder and teat surfaces of the cow is very important and due to the widespread acceptance of the practice of dipping the cows teats in a germicidal agent after milking.
Modern vacuum milking machines have perhaps made teat dipping more critical. Vacuum milking causes a relaxation of the sphincter muscle at the end of the teat canal resulting in an open canal which may require several minutes to hours to contract and close. This open period proffers a direct access route, a veritable highway for microbes, leading to the mammary gland. Dipping the teat in a disinfectant immediately after milking has been shown to be an economical and effective measure in helping to reduce the incidence of mastitis infection. Many disinfectant agents have been used in teat dips, among them: iodine, chlorine, chlorine dioxide, chlorhexidine, fatty acids, anionic surfactants and quaternary ammonium compounds.
These disinfectant agents are generally useful for helping to reduce the bacterial population on the teat skin. Mastitis still persists as the significant dairy cow disease which indicates that the current products do not address all areas of concern. It is an ironic twist that some of the available teat dip agents, notably Iodine and Chlorine, may in fact, contribute to the mastitis problem by causing irritation of the teat skin, thus providing an opportunistic site which promotes infection. Many available teat dip formulations attempt to combat this potential for irritation by incorporating emollient agents in an effort to soothe the skin. Additionally, some of the more powerful disinfectants, chlorine for example, can be particularly noxious for the user as well. Others such as fatty acids and anionic surfactants are not broad enough in their antibacterial spectrum to provide complete protection. Regardless of which germicidal agent is employed or how it is formulated, the ultimate objective of teat sanitation is to minimize teat contamination for as long as possible. It is on this point that conventional teat dips fail. Once germicidal activity of the teat dip ceases, there is no control of environmental pathogens which may be encountered by the teat skin and open mammary canal.
Recent product developments have sought to provide better environmental pathogen protection by bringing forth new teat dips referred to as barrier dips. These products seek to provide an antimicrobial agent, as well as, a coating for the teat skin and a plugging of the open teat canal. One of these products has provided an effective covering of the teat with a latex material (U.S. Pat. No. 4,113,854). This however, has the serious drawback of not being readily removable when the next milking time arrives. The result can be a partially removed coating, leaving behind particles to become trapped in the milk line filters. The difficulties of removal can further result in excessive rubbing of the teat skin, thus leading to irritation. Some of the coating agents tried contain irritants and solvents such as ammonia and even latex has come into question of late due to allergic irritation in human use. Still other products have relied upon weaker antimicrobial agents such as anionic surfactants (U.S. Pat. No. 4,376,787) or are active only at low non-physiological pH values.
There are also barrier products which are essentially thickened teat dips which leave behind a deposit such as cellulose upon drying, These products lack flexibility and tend to crack and flake off, seriously compromising any barrier function by not providing a continuous film of protection. Those products which rely upon a potentially irritating germicide such as iodine must address the potential for skin irritation upon drying which potentially prolongs the iodine contact time and irritation of teat skin. One such product relies upon chlorine dioxide as the germicidal agent. This product has the disadvantages of being a two-part system requiring accurate premixing in the field, of operating at a low non-physiological pH and of losing its germicidal activity over time once it is mixed.